Just as humans can be very different, such as we all have our favorite foods, things we like to wear and places we like to hang out, plants and animals have such preferences too. Unlike us, however, they can’t just change their clothes and go somewhere else.
Plants and animals are well adapted to the habitats they live in. That is why they are there. Some plants grow well with their roots always in the water, so they are found in wetlands where the ground is wet part or all of the year. Other plants need a drier place. Some animals are well adapted for a cold climate and can live in habitats we would consider uncomfortable. Other animals need a more moderate climate.
In addition to their habitat needs, plants and animals also have a job. Most plants are producers, creating oxygen and food for animals. And although we can’t see it, some plants also bring nutrients into the soil and some even act as decomposers and break down other plants.
In the case of animals, their jobs are often more obvious to our eyes. Some, like deer and rabbits, are herbivores and eat just plants. Some, like members of the cat family, are strict carnivores and eat just meat. Many more are omnivores, able to eat plants and animals. Humans are omnivores, along with many birds, raccoons and members of the dog and bear families.
When you combine both habitat needs and an organism’s “job,” you get what is called a niche. The simplest definition is: the position or function of an organism in a community of plants and animals.
Generalists such as coyotes and American crows are animals that do well in most habitats. They can fill many niches. That is why they are so widespread as a species. Their ability to adapt to different climates, habitats and food types also allows them to be less vulnerable to changes in the environment. Animals that have very specific needs are very much affected by change and often become endangered should the conditions change too much across their range. Animals with a very narrow niche are less common, as they do have such particular preferences. One local animal with very particular nesting needs is the marbled murrelet, which is as threatened on the endangered species list.
Even when a species has a fairly nonspecific niche and seems to be doing well, it can sometimes be affected by nonnative species coming in and outcompeting the native species. It is almost like if a job were to open up and the hiring authority used a “Hunger Games”-type of competition to determine who wins the space. The strongest, most aggressive competitors have the edge.
In the case of local western pond turtles, they are often out-competed by the red-eared sliders and other species of turtles introduced to wetlands by people. The native western pond turtle is listed as endangered by the state, mainly due to overall habitat loss, but also partly because of competition from nonnative turtles.
Nonnative animals should not be released into the wild. The main reason is because it is not fair to them. They are nonnatives for a reason. This is not their appropriate habitat and they could have a very difficult time surviving here. Or, even worse ecologically, they could out-compete natives and establish a local population that negatively affects many native species. Bullfrogs are an example of an animal that does not belong here, but has become well-established, to the detriment of native populations of other frogs and other wildlife.
Likewise, nonnative plants are not only much more expensive to maintain, sometimes costing as much as 200 times more to keep up, but they can sometimes cause problems for native plants. Native plants belong here. They evolved with the soils, the climate, the wildlife, even the beneficial insects of this area. They thrive in this local climate without much interference from us and contribute to the local community of wildlife and other plants. In other words, they don’t need much in the way of added water, fertilizer or pesticides.
In order to have the most cost-effective and beneficial yard for wildlife, the majority of plants used in landscaping should be natives. It is fine to mix in some nonnatives for extra color or because you enjoy a particular plant, but be careful to avoid those that are on the invasive species list. They should never be planted on purpose. Plants such as English ivy and Scotch broom should not only never be planted on purpose, but they should be removed before they spread farther. You can visit the Washington Native Plant Society’s website (wnps.org) for more information on what the right plants are for your yard